public static extern IntPtr GetItemBkInfoManager(IntPtr hEle, XTreeItemState nState);
public static extern int GetItemBkInfoCount(IntPtr hEle, XTreeItemState nState);
public static extern IntPtr ClearItemBkInfo(IntPtr hEle, XTreeItemState nState);
public static extern IntPtr AddItemBkImage(IntPtr hEle, XTreeItemState nState, IntPtr hImage);
public static extern IntPtr AddItemBkFill(IntPtr hEle, XTreeItemState nState, int color, byte alpha);
public static extern IntPtr AddItemBkBorder(IntPtr hEle, XTreeItemState nState, int color, byte alpha, int width);